MR-morphologische Kriterien perimesencephaler Venen bei nicht traumatischen Subarachnoidalblutungen anhand von SWI-Sequenzen

Als Subarachnoidalblutung wird eine intrakranielle Blutung beschrieben, welche häufig in Folge eines rupturierten Aneurysmas entsteht. In ca. 20% der atraumatischen SABs kann jedoch trotz wiederholter, invasiver diagnostischer Maßnahmen (digitale Subtraktionsangiographie) keine Blutungsquelle gefunden werden. Hierbei handelt es sich häufig um perimesencephal gelegene Blutungen. Van Gijn et al. (1985) definierten diese als nichtaneurysmatische, perimesencephale SABs. Eine venöse Blutungsursache gilt bei dieser Blutung als wahrscheinlicher als eine arterielle, da der klinische Verlauf dieser Patienten häufig milder verläuft als bei Patienten mit einer aneurysmatischen SAB. Zudem kommt es bei dem perimesencephalen Blutungstyp einerseits weniger häufig zu Komplikationen wie z.B. einem Hydrozephalus, einer VP-Shunt-Indikation, einem Vasospasmus oder einem Infarkt als auch andererseits zu einem besseren klinischen Behandlungsergebnis

Broker Models for Mass Customization Based Electronic Commerce

While the competitive advantage of mass customization has been widely substantiated in management theory since more than a decade, its implementation in business can be observed just within the last years. In this paper we demonstrate how modern Internet technologies and possibilities of e-business work as success factors for mass customization. Especially, we deploy how intermediaries can add new value to mass customization based business models in electronic commerce

Helios spacecraft data revisited: Detection of cometary meteoroid trails by in-situ dust impacts

Cometary meteoroid trails exist in the vicinity of comets, forming fine structure of the interplanetary dust cloud. The trails consist predominantly of cometary particles with sizes of approximately 0.1 mm to 1 cm which are ejected at low speeds and remain very close to the comet orbit for several revolutions around the Sun. When re-analysing the Helios dust data measured in the 1970s, Altobelli et al. (2006) recognized a clustering of seven impacts, detected in a very narrow region of space at a true anomaly angle of 135 deg, which the authors considered as potential cometary trail particles. We re-analyse these candidate cometary trail particles to investigate the possibility that some or all of them indeed originate from cometary trails and we constrain their source comets. The Interplanetary Meteoroid Environment for eXploration (IMEX) dust streams in space model is a new universal model for cometary meteoroid streams in the inner solar system, developed by Soja et al. (2015). Using IMEX we study cometary trail traverses by Helios. During ten revolutions around the Sun, and in the narrow region of space where Helios detected the candidate dust particles, the spacecraft repeatedly traversed the trails of comets 45P/Honda-Mrkos-Pajduvsakova and 72P/Denning-Fujikawa. Based on the detection times and particle impact directions, four detected particles are compatible with an origin from these two comets. We find a dust spatial density in these trails of about 10^-8 to 10^-7 m^-3. The in-situ detection and analysis of meteoroid trail particles which can be traced back to their source bodies by spacecraft-based dust analysers opens a new window to remote compositional analysis of comets and asteroids without the necessity to fly a spacecraft to or even land on those celestial bodies. This provides new science opportunities for future missions like Destiny+, Europa Clipper and IMAP.Comment: 13 pages, 9 Figures, 2 Tables, accepted for pubication by Astronomy and Astrophysic

Teaching Media -- Medientheorie für die Schulpraxis – Grundlagen, Beispiele, Perspektiven (unter Mitarbeit von Linda Leskau, Kathrin Lohse, Arne Malmsheimer und Jens Schröter)

Nowadays, media determine the daily routine of schools. But what are media? How has media been fought about over the centuries? This volume offers the foundations for a qualified confrontation with questions of media reflection and the use of media in school praxis. A historical overview shows the structures of the debates around the possibilities and dangers of the use of media, and thus serves to make the debate more objective. The comprehensible and competent representation of the central concepts, developments and discoveries of media theory make this book essential reading for students in education and student teachers from diverse subject areas.Medien bestimmen heute im Unterricht und auf dem Schulhof den Schulalltag. Demgegenüber steht allerdings häufig die Unsicherheit darüber, wie Medien »richtig« genutzt werden können, was Medien überhaupt sind und was sie zu leisten vermögen. Dieses Buch macht fit für eine kompetente Medienerziehung an der Schule! Angehende und erfahrene Lehrer_innen erhalten einen historischen Überblick über die Kontroversen um Chancen und Gefahren der Mediennutzung, eine Auswahl von kommentierten Auszügen klassischer Texte zur Medienreflexion sowie konkrete Anregungen zu einem medienkundlichen Unterricht. Die verständliche und an den Bedürfnissen des Schulunterrichts orientierte Darstellung der zentralen Konzepte, Entwicklungen und Erkenntnisse der Medientheorie und -geschichte machen den Band zur Pflichtlektüre für Lehramtsstudierende, Referendar_innen und Lehrer_innen unterschiedlicher Fachrichtungen

Sweet Taste Receptor Expressed in Pancreatic β-Cells Activates the Calcium and Cyclic AMP Signaling Systems and Stimulates Insulin Secretion

BACKGROUND:Sweet taste receptor is expressed in the taste buds and enteroendocrine cells acting as a sugar sensor. We investigated the expression and function of the sweet taste receptor in MIN6 cells and mouse islets. METHODOLOGY/PRINCIPAL FINDINGS:The expression of the sweet taste receptor was determined by RT-PCR and immunohistochemistry. Changes in cytoplasmic Ca(2+) ([Ca(2+)](c)) and cAMP ([cAMP](c)) were monitored in MIN6 cells using fura-2 and Epac1-camps. Activation of protein kinase C was monitored by measuring translocation of MARCKS-GFP. Insulin was measured by radioimmunoassay. mRNA for T1R2, T1R3, and gustducin was expressed in MIN6 cells. In these cells, artificial sweeteners such as sucralose, succharin, and acesulfame-K increased insulin secretion and augmented secretion induced by glucose. Sucralose increased biphasic increase in [Ca(2+)](c). The second sustained phase was blocked by removal of extracellular calcium and addition of nifedipine. An inhibitor of inositol(1, 4, 5)-trisphophate receptor, 2-aminoethoxydiphenyl borate, blocked both phases of [Ca(2+)](c) response. The effect of sucralose on [Ca(2+)](c) was inhibited by gurmarin, an inhibitor of the sweet taste receptor, but not affected by a G(q) inhibitor. Sucralose also induced sustained elevation of [cAMP](c), which was only partially inhibited by removal of extracellular calcium and nifedipine. Finally, mouse islets expressed T1R2 and T1R3, and artificial sweeteners stimulated insulin secretion. CONCLUSIONS:Sweet taste receptor is expressed in beta-cells, and activation of this receptor induces insulin secretion by Ca(2+) and cAMP-dependent mechanisms

The CPT1C 5′UTR Contains a Repressing Upstream Open Reading Frame That Is Regulated by Cellular Energy Availability and AMPK

BACKGROUND: Translational control is utilized as a means of regulating gene expression in many species. In most cases, posttranscriptional regulatory mechanisms play an important role in stress response pathways and can lead to dysfunctional physiology if blocked by mutations. Carnitine Palmitoyltransferase 1 C (CPT1C), the brain-specific member of the CPT 1 family, has previously been shown to be involved in regulating metabolism in situations of energy surplus. PRINCIPAL FINDINGS: Sequence analysis of the CPT1C mRNA revealed that it contains an upstream open reading frame (uORF) in the 5' UTR of its mRNA. Using CPT1C 5' UTR/luciferase constructs, we investigated the role of the uORF in translational regulation. The results presented here show that translation from the CPT1C main open reading frame (mORF) is repressed by the presence of the uORF, that this repression is relieved in response to specific stress stimuli, namely glucose deprivation and palmitate-BSA treatment, and that AMPK inhibition can relieve this uORF-dependent repression. SIGNIFICANCE: The fact that the mORF regulation is relieved in response to a specific set of stress stimuli rather than general stress response, hints at an involvement of CPT1C in cellular energy-sensing pathways and provides further evidence for a role of CPT1C in hypothalamic regulation of energy homeostasis

Reconstructing the Deep Population History of Central and South America

We report genome-wide ancient DNA from 49 individuals forming four parallel time transects in Belize, Brazil, the Central Andes, and the Southern Cone, each dating to at least 9,000 years ago. The common ancestral population radiated rapidly from just one of the two early branches that contributed to Native Americans today. We document two previously unappreciated streams of gene flow between North and South America. One affected the Central Andes by 4,200 years ago, while the other explains an affinity between the oldest North American genome associated with the Clovis culture and the oldest Central and South Americans from Chile, Brazil, and Belize. However, this was not the primary source for later South Americans, as the other ancient individuals derive from lineages without specific affinity to the Clovis-associated genome, suggesting a population replacement that began at least 9,000 years ago and was followed by substantial population continuity in multiple regions

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

Abstract: In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M ⊙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded